Termination of fiber optic cables is a predominantly manual process. This is largely due to the fragile nature of the glass fibers, and the mix of materials and processes required to form a stable interface. In other words, the process of gluing the small diameter fiber within a tight tolerance zirconia ferrule, cleaving it without damage, and polishing it to a defect-free surface involves a great deal of care, and multiple steps. Efforts to automate the process, and eliminate the craft necessary to achieve good performance, have been generally unsuccessful.
Traditionally, cleaving of the optical fiber is performed using a scribe tool with a sapphire, ruby or carbide tip. A careful operator has to scribe the fiber just above the cured epoxy and gently pull the tip of the fiber parallel to the fiber axis without producing a crack. When not done properly, this resulting crack often makes the termination unusable. This operator has to be one of the more careful and conscientious people in the factory, and may perform this same repetitive job for much or all of an entire shift. If a crack does result from the scribing procedure, the connector needs to be cut off and the entire process needs to be redone. On breakout cables with many fibers, cracks can create other problems. If breakouts are at precise lengths, all ends would need to be redone.
After the cleave, a manual denubbing process takes place to take the fiber stub down to the epoxy, so that it does not crack during the epoxy removal step. This step can be time consuming and very operator dependent. The connector end face can also be deformed if the procedure is not done properly, and such deformation is typically undetected until testing. With a manual cleave, traditional machine polishing requires four to five steps using silicon carbide, diamond and silicon dioxide lapping films with rubber pads after the denubbing—epoxy removal, multiple geometry end face forming, and the final—to reform the geometry of the connector.
A new cleaving technique, using a CO2 laser, largely automates the process. The operator simply places the connector into the laser cleaver, the laser scans across the fiber and epoxy bead, and it cleaves both together. The human factor is eliminated from the cleaving and denubbing steps. However, laser cleavers tend to expensive, and also may introduce a radiation hazard. Additionally, laser cleaves operate at relatively high temperatures and can require shielding to prevent damage to portions of an optical fiber near the laser cleave location thereby adding to system complexity.
In view of the foregoing, it may be desirable to propose additional cleaving techniques.